An illumination unit for emitting lights with various colors has been conventionally proposed (Patent Literature 1, for example). The illumination unit includes an R (red) light source, a G (green) light source, and a B (blue) light source, and can change illumination colors by adjusting luminance of each light source.
In the illumination unit, a table of RGB values corresponding to each illumination color is stored, and a microcomputer for controlling the light sources reads a RGB value of a desired illumination color from the table, and adjusts the luminance of the light sources according to the read RGB value.